Media Express capture issue: Video slows down, drops audio..

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JB@CLC

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Media Express capture issue: Video slows down, drops audio..

PostTue Nov 20, 2012 7:06 pm

Hello all.

During playback of 720P video... the footage is bogging down and the audio is dropping out.. and it happens like every 10-15 seconds or so.

I am pretty sure the speed of my computer is to blame but I wanted to post this question to you all here.

I have a single Quad Core HPZ600 E5640 2.66GHZ workstation with 4GB of RAM. It's outfitted with Blackmagic Decklink HD Extreme 3D capture card and a Nvidia Quadro FX 1800 graphics card. It also has a 500GB system drive, a separate internal 3 TB A/V capture drive and an external 4TB G-Raid drive. I am attempting to capture a scaled 4:3 image that is coming out of a Kramer VP727 dual scaler mixer within the 720P frame in Media Express. In the task manager.. the CPU load is only about 13% but the system Physical Memory is running at about 50%.

Before you ask.. yes I have run the Blackmagic Disk Speed application and it says that the speed of the computer can only capture SD NTSC or PAL. So it seems obvious that my computer is not fast enough. The problem with that for me is that Media Express only captures NTSC 720x486i 59.94 and my mixer only outputs 480P! So.. although I would LOVE to settle with SD.. I can't even do that. My only option is 720P.

So.. I want to ask my supervisor if we can upgrade to a 2nd matching Quad Core and some more memory but i wanted to get someone's input from here.

I can furnish whatever further information you might need... if you can help me iron out this issue.. I would appreciate it very much.

Thanks a lot,

JB
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Joshua Helling

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Re: Media Express capture issue: Video slows down, drops aud

PostTue Nov 20, 2012 7:55 pm

Hello,

In this case it would definitely seem as if your hard drives are just not keeping up with the demands of the video you are capturing.

There are a couple of ways you could potentially tackle this.

IF you really want to use uncompressed (which is almost definitely what you are using), you would want to get a larger more robust hard drive array. A single drive is not cutting it in this case. if you have more room in your chassis I'd recommending another 2 (at least) possibly 3 of these drives. Then you can set those drives up in a RAID-0 and that should be plenty fast to accomplish what you are looking to do.

If you are open to the idea of using a compressed codec you could use the MotionJPEG codec that we include with our software package. The datarate on this codec is much smaller (at the cost of some additional CPU overhead, which you have plenty of). It has a datarate of around 17-20Mb/second. A single drive should be able to handle this fine.

I don't think that adding another computer in this case is gonna be the best way to go here as it does nothing to address the real concern of the hard drive speed.
Joshua Helling

Director of World Wide Support
Blackmagic Design Inc.
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JB@CLC

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Re: Media Express capture issue: Video slows down, drops aud

PostTue Nov 20, 2012 8:09 pm

Joshua,

Thank you for the reply.

I do not have any more internal space for a RAID set up. The Z600 only has space for 2 HD's BUT... I do have 3 more eSATA connectors on the motherboard. Does this mean I can hook up an external RAID config?

BTW.. you mean a Striped Array right? Not Mirrored.

And would it be possible to set up my G Raid drive to be useable in this fashion? It has a eSATA connection but I have been using the FW800.

Here are the Specs.. it is a dual drive.. and can be set up for RAID 0!

http://www.macmall.com/p/G-Technology-E ... dp.gbedbaa

I have also been reading up on 10K hard drives. Is this a reasonable solution too?

I appreciate your input!

JB
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Joshua Helling

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Re: Media Express capture issue: Video slows down, drops aud

PostTue Nov 20, 2012 8:57 pm

Esata would work fine in this situation.

Yes, stripped (RAID0) is the way to go. If you Mirror (that's RAID1) then you will not get a performance increase, but will have full redundancy.
Joshua Helling

Director of World Wide Support
Blackmagic Design Inc.
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JB@CLC

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Re: Media Express capture issue: Video slows down, drops aud

PostTue Nov 20, 2012 9:05 pm

OK Gotcha! I will try this solution!!!!!!

Thank you for the input!!!

Kudos!

JB
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JB@CLC

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Re: Media Express capture issue: Video slows down, drops aud

PostWed Nov 21, 2012 7:55 pm

I just got off the phone with G-RAID Tech support.

they said that I can try to run it over the FW800 port first.. to see if I can make a solid recording. They said that the RAID0 Drive configuration over FW800 SHOULD be faster then the internal SATA drive but not faster then the eSATA connection.

I will try it on Monday and report back then!

JB
Last edited by JB@CLC on Wed Nov 28, 2012 2:37 pm, edited 1 time in total.
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JB@CLC

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Re: Media Express capture issue: Video slows down, drops aud

PostMon Nov 26, 2012 7:32 pm

I tried to capture to the RAID0 G Tech Drive via FW 800 and the video playback is still choppy but choppy in a different way. Instead of the video slowing down and dropping audio every 15 seconds.. the video is choppy in general but it doesn't drop audio at all now. So.. I think capturing the RAID array worked better but the FW800 connection seems like its still not fast enough. I would say that the eSATA connection would PROBABLY be the better connection and that I will probably need a G Tech RAID Controller to achieve the quoted 200MB's per second performance level.

Joshua... do you think the FW800 capture SHOULD be fast enough or is it just too slow for capturing live 720P??

Any input fro anyone would be great!

Thank you very much.

JB
Last edited by JB@CLC on Wed Nov 28, 2012 2:36 pm, edited 1 time in total.
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JB@CLC

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Re: Media Express capture issue: Video slows down, drops aud

PostMon Nov 26, 2012 7:57 pm

I just ran the BMD Disk Speed test on the drive over the FW800 connection...

FW800

Write: 70MB/sec
Read: 87.5MB/sec

This is slower then the internal SATA connection!!!

SATA

Write: 90MB/sec
Read: 90MB/sec

So G Tech rates their eSATA controller up to 300MB/Sec and they SAY its required to be able to use the RAID feature.

http://www.provantage.com/g-technology- ... TEC04V.htm

So I guess this means I NEED their card right? Or can I go with any eSATA controller?

Also... I have empty SATA ports on my mother board... can a SATA to eSATA adapter cable make it work or not?

http://www.newegg.com/Product/Product.a ... -_-NA-_-NA
Last edited by JB@CLC on Wed Nov 28, 2012 2:36 pm, edited 1 time in total.
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JB@CLC

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Re: Media Express capture issue: Video slows down, drops aud

PostTue Nov 27, 2012 5:57 pm

As I stated before my video mixer only outputs 480P and that is not recognized by the Media Express software's NTSC 8 bit setting. So I disconnected the video mixer and hooked up the camera directly into the capture card. I set the video output to the 720p/480i setting and then made a recording. The video image captures into Media Express perfectly but only on the camera's 720P/480i combo setting and not on the 480i setting by itself. Not sure what the difference is...

Anyway... the problem with this is that my video mixing board only outputs 480p and BMD Media Express doesn't capture 480P.

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